Electrically-driven percussive tool.



L. scHUuzR.

ELECTRICAILY DRIVEN PERCUSSIVE TOOL.-

APPLICATION FILED MAY 22, 1915.

1,203,138. Patented Oct. 31,1916.

vWfimswses: In venfar':

/KW L80 Sci-101617 5. by M m: mmms rzrnu co.. PNOYV-LIYNOM wAsmNcruN. u. c.

UNITED STATES PATENT OFFICE.

LEO SCH'ULER, OF LICHTERFELDE, NEAR BERLIN, GERMANY.

ELECTRICALLY-DRIVEN PERCUSSIVE TOOL;

Application filed May 22, 1915.

To all whom it may concern Be it known that I, Lno Sorrr'innn, engineer, a subject of the German Emperor, residing at Tulpenstrasse 5, Lichterfelde, near Berlin, Germany, have invented certain new and useful Improvements in Electrically- Driven Percussive Tools, of which the following is a specification.

The object of this invention is the combination of a mechanical percussive tool with an electro-motor of special type; the special features of the electromotor are very light weight and at the same time high flywheelefiect which is of special importance in percussive tools as power is only required dur ing a small part of a revolution. In order to obtainthis result the rotor of the motor is arranged outside the stator, while in ordinary motors the contrary is the case.

The figure shows as an example a handhammer whereby the motor is a polyphaseinduction-motor.

1 is the stator-iron which is supported by a hub attached to the case, 2 the statorwinding, 3 the rotor-iron, 4 the rotor-winding (squirrel-cage-winding). The rotor is supported by spokes 5 attached to the hub 6 which is carried by the shaft 7. One of the rotor-spokes carries the pin 8 which drives by means of the connecting rod 9 the hammer-mechanism. The latter can' be of any suitable design and need not be described. Instead of the spokes 5 of course a full disk can be used.

The advantages of this arrangement are specially important for induction-motors, as in these the rotor can be made of solid steel whereby a very simple construction is obtained. Furthermore the iron-losses are much smaller as the weight of the statoriron is much smaller when the stator is arranged inside the rotor. Finally it must be taken in consideration that the stator-iron must, with regard to iron-losses, be worked at low saturation (about 8000) while the rotor-iron can be Worked at a much higher saturation (about 16000); now, when the high-saturated part is arranged outside a considerable reduction of the total weight is obtained. Only in this way it has become possible to produce apractical and handy percussive tool with directly attached elec- Specification of Letters iatent.

Patented Oct. 31, 1916.

Serial No. 29,823.

tromotor, while it was necessary so far in consequence of the heavy weight of the usual motors to drive the hammer by a separate motor by means of flexible shafts or the like.

Motors with outside rotor have been known before, but they could not be used for ordinary power purposes as the mechanical construction is too difficult. Now in the application of such motors for driving hammers the mechanical difliculties are fully avoided by the construction shown in the drawing. The invention is suitable for all kinds of percussive tools for chiseling, riveting and all other purposes.

\Vhat I claim and desire to secure by Letters Patent of-the United States is 1. In an electrically actuated percussive tool, the combination as a portable unit, of a motor, a stator for said motor, a rotor embracing said stator, a hammer operatively connected to said rotor so as to be reciprocated thereby and a tool operated by said hammer.

1 2. In an electrically actuated percussive tool, the combination as a portable unit, of a motor, a stator for said motor, a rotor embracing said stator, a rotatable member firmly connected to said rotor, a hammer connected to said rotatable member so as to be reciprooated thereby and a tool operated by said hammer.

8. In an electrically actuated percussive tool, the combination as a portable unit, of a motor, a stator for said motor, a rotor embracing said stator, a rotatable member firmly connected to said rotor, a crank on said rotatable member, a hammer connected to said crank so as to be reciprocated thereby, and a tool located in the path of movement of said hammer so as to be struck thereby.

4. In an electrically actuated percussive tool the combination as a portable unit, of an induction motor, a stator for said motor, a rotor embracing said stator, a hammer, crank-mechanism for operatively connecting said hammer to the rotor and a tool located in the path of travel of said hammer.

5. In an electrically actuated percussive tool, the combination as a portable unit, of an induction motor, a stator for said motor,

:1- rotor embracing said stator, a rotatable In witness whereofIhave hereunto set my member secured to szud rot-01', a crank on hand In the presence of a witness. sud lotatable lnelnbel, a hannnei connected LEO SCHULER to the said crank so as to be i'eciprocated 5 thereby, and a tool located 111 the path of fitness:

travel oi sand hammer. HENRY HASPER.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Yatents.

Washington, I). C. 

